a. Field of the Invention
The present invention relates to catheters employed for diagnostic and/or therapeutic procedures in medicine, more specifically in minimally invasive cardiac electrophysiology studies and/or cardiac ablation procedures.
b. Background Art
It is known from the inventors' prior patents and pending applications to provide a pair of tension and compression members (such as push/pull wires) that cooperate to selectively actuate a distal end of a catheter. The distal end typically carries axially-spaced electrodes which, when located in the body passage such as the heart, monitor and record intra-cardiac electrical signals during desired studies or intracardiac mapping procedure. As is known, the electrodes conduct the cardiac electrical signals to monitoring and recording devices. In addition, the electrodes may be used to deliver electrical energy to selectively destroy a site of cardiac tissue that causes an arrhythmia or abnormality in the heart rhythm.
It is important for these types of procedures that wires extending through the catheter for connection with the electrode be of sufficient size to carry desired electrical energy levels to perform these procedures. It is also important that a distal portion of the catheter be able to deflect into a variety of configurations, typically curved configurations having selective radii of curvature in response to actuation from a catheter handle. U.S. Pat. Nos. 5,552,713 and 5,861,024 are commonly owned by the assignee of the present application and show and describe in detail preferred catheter embodiments of this type. The disclosure and details of these patents are expressly incorporated herein by reference. The actuating mechanism described in the patents is ergonomic, easy to operate, requires a relatively low force to form a desired curvature of the catheter distal portion, allows a comfortable range of displacement of the actuator to provide a full range of curvature formation of the catheter distal portion, and permits for curvature formation and curvature retention by a single action of the physician's hand. These desired features are all achieved through side-by-side longitudinal reciprocation of tension/compression members that cooperate to provide simultaneous tension in one member or wire, and compression in the other member or wire. The tension/compression members preferably have a generally circular cross-section throughout a major portion of their length and a generally flattened, ribbon-like configurations adjacent the distal portion of the catheter. A kinematic junction is provided on the ribbon-like portions of the tension/compression members. Bi-directional curvature or lateral deflection is thus provided by employing tension/compression members without the need of a compression strut in the distal portion. Typical dimensions of a catheter casing, electrodes, and diametrical curvature upon actuation are set forth in greater detail in commonly owned U.S. patent application Ser. No. 09/726,235, (Publication No. US-2002-0065514-A1, published May 30, 2002), the details of which are also incorporated herein by reference.
It is known from U.S. Pat. No. 6,325,797 to use an inflatable balloon that is selectively pressurized from an associated liquid source. A lumen is formed within the catheter and carries the liquid, such as saline, to the balloon. In this manner, the balloon is selectively inflated to engage the inner wall of an intracardiac vessel, for example the pulmonary vein wall.
However, a need exists for an electrophysiology lumen catheter that provides effective minimally invasive cardiac diagnostic electrophysiology and/or cardiac ablation procedures, that also provides a flexible liquid delivery tube within the shaft of the catheter, and still maintains all of the benefits of bi-directional deflection and curvature configurations.